Cardiovascular events remain largely unpredictable. However, recently, inflammation has been recognized as being associated with the formation and progression of vulnerable plaque. It has been observed that the inflamed necrotic core of a vulnerable plaque deposit, is a fraction of a degree to a few degrees higher than the surrounding tissue. MSI proposes to develop an optical thermal mapping catheter (OTMC) for real-time temperature monitoring of a vessel wall, with high sensitivity, accuracy, and ease of use. The technology is based on ultra thin optical fibers, encoded with optical gratings derived from state-of-the-art optical fiber communication. Fiber gratings reflect light of particular bandwidths and can act as high-performance optical thermal sensors. The reflected bandwidths are extremely narrow. A minute temperature change around the fibers, changes the effective refractive index, and leads to modulation of reflective wavelengths. The proposed OTMC, incorporates multiple optical fibers into a basket catheter that can simultaneously map thermal distribution in-situ. Phase I work will focus on the design & fabrication fiber gratings, constructing a basket catheter with built-in optical fibers, integration of the optoelectronics, followed by the testing and characterization of the system's performance.